Viscosupplementation is a medical procedure during which lubricating fluid is injected into a joint. In this procedure, a gel-like fluid called hyaluronic acid is injected into the affected joint.

Hyaluronic acid is a naturally occurring substance found in the synovial fluid surrounding joints. Hyaluronic acid (high molecular weight hyaluronan) is a complex sugar used to treat pain in osteoarthritis (OA) in patients who have failed to respond adequately to conservative non-pharmacologic therapy or simple pain medications (analgesics). It acts as a lubricant to enable bones to move smoothly over each other and as a shock absorber for joint loads. People with osteoarthritis have a lower-than-normal concentration of hyaluronic acid in their joints. The theory is that adding hyaluronic acid to the arthritic joint will facilitate movement and reduce pain. Viscosupplementation injections are intended to help return some of the mobility and function to the affected joints.